Aluminum Sesquichlorohydrate

Aluminium sesquichlorohydrate is an inorganic salt derived from aluminium chloride. It functions as an antiperspirant rather than a deodorant, meaning it works to reduce the volume of sweat produced rather than simply masking odour. The ingredient is commonly used in concentrations between 10% and 25% in antiperspirant formulations.

When applied to the skin, it creates a physical barrier that partially blocks eccrine sweat gland ducts, thereby decreasing sweat secretion at the source. Because antiperspirants inherently reduce moisture on the skin's surface, they also prevent the bacterial breakdown of sweat that causes odour.

Aluminium sesquichlorohydrate undergoes hydrolysis when it contacts moisture on the skin, releasing aluminium ions. These ions form a plug-like complex within the sweat gland duct, physically obstructing the flow of sweat to the skin surface. This mechanism is distinct from deodorants, which mask or neutralise odour rather than preventing perspiration.

Because this hydrolysis process is acidifying, formulations typically include emollients and pH regulators to minimise irritation and maintain skin comfort during regular use.

Apply aluminium sesquichlorohydrate products to clean, dry skin, typically at night before bed to allow maximum contact time with sweat glands. Initial protocols often involve nightly application for 1–2 weeks, followed by a maintenance schedule of 2–3 times per week. If irritation develops, reduce frequency or discontinue use and allow the skin to recover. Formulations designed with lower residue or foam bases may be gentler if you have sensitive skin.